Here is the full list of all 23 Featherpunk Prime achievements.
Completed First floor.
Take down Guardian 1.
Take down Guardian 2.
Take down Guardian 3.
Take down Guardian 4 and destroy Cybirdroid.
Activate the checkpoint.
Destroyed 10 times.
All Sector 1 collectibles collected.
All Sector 2 collectibles collected.
All Sector 3 collectibles collected.
All Sector 4 collectibles collected.
Every collectible in every sector collected.
Complete the Boss 1 without dying.
Kill 500 enemies.
Kill first sentinel.
A funky hat for F-Droid.
Completed the tutorial.
Kill 100 enemies during Overdrive.
Less than 10 health pickups used.
Complete the game with killing all Guardians the first time.